Brake ducts/cooling

[MR22ZZ]

I think it may be the pads Joel, I have a similar problem with my bendix fronts. Also after about 8-10 laps.
Also what sort of condition are the lines in? Any bubbles?

[web]

Right... pedal to the floor is a fluid problem, not a pad problem, that is if the MC is good.

A pad change isn't going to fix this. Pad fade gives you a hard pedal but not slowing down.

So... bandaid fixes would be:
- DOT 5.1 for the higher boiling points. Fluid should be changed after "pedal to floor" boiling incidents anyway.
- I'd try to direct cooling ducts at least partially at the caliper, in hopes of helping it get rid of the fluid heat. Cooling via the disc has less effect on caliper temperature, where you need it the most.

The only "real" fix would be an increase of rotor surface area e.g. go even larger. Stock brakes might have lasted 2-3 laps or less. However, track racing is hell on brakes, apparently enough so, that even your current setup lasts just 10 laps.

Another bandaid - one to be applied with much care - could be a water spray. You need a fine mist if you don't want warp or even crack stuff, and never mind the steam clouds

[WDE_BDY]

Decent pads also transfer less heat to the caliper, so you will keep a lower fluid temp.

Callum

[The Real Roadrunner]

Right... pedal to the floor is a fluid problem, not a pad problem, that is if the MC is good.

A pad change isn't going to fix this. Pad fade gives you a hard pedal but not slowing down.

So... bandaid fixes would be:
- DOT 5.1 for the higher boiling points. Fluid should be changed after "pedal to floor" boiling incidents anyway..

this is arguable,

now while it is a fluid problem (pedal to floor) its caused by the pads, it can be fixed by using the appropriate pad for the situation, if your not on the brakes as long they wont build anywhere near the amount of heat up nor will it cook the fluid at the same time.

i believe a simple pad change and fluid flush will cure this problem in an afternoon as the rotor mass is reasonably sized to the Hp and weight.

Not all pards give a hard pedal when hot, most good pads will keep their braking capability but suffer from excessive wear, cheaper pads will just crap themselves when overheated.

I would also opt for a 5.1 or synthetic fluid for consistency, but having said that in my own vehicle i just run fresh 4.0 as i havn't ever had a fade problem with it.

cheers
linden

edit, darn you wide body, beat me to posting but mines a better explanation

[merc-blue]

OK WELL.
Brake ducts ducting internaly arent always the best you need to ensure that you have the correct vaned rotors for this style of setup other wise you can possibly stall the air inside the rotor and make the situation worse.

Get better fluid castrol SRF is the shit, but assuming 100 bux for only one liter is not what you want to spend get the AP racing stuff its cheaper (40-50 dollars a liter) and should be adequate,
Get Brake paint so you can monitor your brake systems temperature and choose pads that are suitable,
Get Pads to suit the temps your seeing from your rotors,
I can assure you producing a brake duct will cost you more than more track aimed pads and fluid the tube that you would require (assuming your melting bendix ultimates) is in the order of 150-200 dollars a meter, its a resin injected fibreglass flex tube anything else will have a very short life time, melting or splitting and becomming inaffective,

If you do produce a duct use fiberglass with a high temp resin or carbon not alloy as the alloy ones transmit head into your tubes and fry it.

Idealy 2 ducts would be best one ducting air into the center of the rotor (assuming you have vaned rotors that pump air out) spin one up on a lathe and feel the air flow to check it working correctly some straight vaned rotors dont do this.

and a second smaller duct just blowing air onto the caliper, remember that the calipers are a big chunk of metal that hold alot of head but also have alot of surface area so you can keep your brakes cool with that aswell.

If your really concerned we can start talking casselated pistons and such,

[Draven]

ps: hawk HT-10 pads are the shit

[SuperDave]

I'd start with the fluid since you lost the pedal. Change/upgrade fluid

From what I have found the Bendix Ultimates have a temp range only to 550*C, far too low for stopping 1100kg; obviously depends on the speeds your stopping and how often. My car weighs about 1200kg and in my experience 550*C pads aren't up to the task, go to a higher temperature.

[sleeektoy]

Be very careful when ducting to the rotors - esp. vented ones.
usually a lot of ducting gets pointed at the inside of the rotor and cools the inside half of the rotor but not the outside. this creates some very interesting expansion/contraction on the rotors and wears them in unusual ways.

try to evenly vent them.

the reason - A week long rally and 3 days into it we replaced front rotors twice.(radial cracks on the outer part of the rotor) removed the ducting and ran the rest of the rally no probs.

[HighLife]

Maybe these will help?

http://cgi.ebay.com.au/FPR-BRAKE-DUC...QQcmdZViewItem

[MR22ZZ]

Maybe these will help?

http://cgi.ebay.com.au/FPR-BRAKE-DUC...QQcmdZViewItem

F**K me that is the best find ever...

for those that don't know... BRITECK MOTORSPORT CLEARANCE SALE on E-BAY!!!

http://stores.ebay.com.au/britekmoto...dZ2QQpZ7QQtZkm

those hose fittings are damn tempting

anyone got a spare $300,000 for 2, yes 2, not 1 but 2!!! V8 supertaxis.

[Draven]

yeah, only $900!

Stimulus brake ducting

[Sciflyer]

Aeroduct is the shit you want to use, its the orange silicon stuff you see on race cars

[merc-blue]

No aeroduct is not, its breaks from the repeditive movement and doesnt handle temps aswell as it prompts you to beleive.

The stuff you want is a resin injected fibreglass tube with wire in it normaly sewed in with kevlar thread. its the only shit worth using if your not into constantly replacing it.

[web]

this is arguable,

now while it is a fluid problem (pedal to floor) its caused by the pads, it can be fixed by using the appropriate pad for the situation, if your not on the brakes as long they wont build anywhere near the amount of heat up nor will it cook the fluid at the same time.

Slowing down is simply getting rid of kinetic energy. Whether you do it fast or slow, slowing down for corner X will generate the same amount of heat, irrespective of what pad you use to do it. A pad that slows you down quick, will simply convert kinetic energy to heat faster than other pads. There's no other way to rub off speed than convert it to heat.

That said, I'm sure some pad designs/materials conduct more of that heat to the caliper than others - so I stand corrected, pad choice CAN have an effect on fluid fade. I guess a tough but insulating shim could help too. Come to think of it, some pads already have a thin layer of insulating backing. I seem to remember my Bimmer has it. I thought they were meant to replace anti squeal shims but

i believe a simple pad change and fluid flush will cure this problem in an afternoon as the rotor mass is reasonably sized to the Hp and weight.

I'm not so convinced about that for all out track racing, but I don't know the weight or the type of track, so it's hard to say. 283x22 may be copious for the street, but not THAT huge.

[-GT-]

Joel, my vote is for good pads and fluid first too - can make a huge difference. Bendix are not going to be up to the task of sustained track time (ie more than a few laps) - don't be shy about going something pretty serious pad-wise; the suggestions to check brake temps and match a pad to that is a good one. Definately worth getting track-only pads as, like everything else, street and track is always going to be a compromise. Great if you can manage to find some that does both as it saves you the hassle of changing, but really, they're pretty different uses so you're doing well to get something good at both.

Fluid too; i've been using the motul rbf600 and really like it, even though it's $50/L. Couldn't get it last time and had to use Penrite Sin (600+ deg boiling pt same as ) and have been damn impressed. It was a fair bit cheaper too!

I'll still change fluid every couple of track days unless it's been ages in between or i cooked it; then it gets done after one.

If you're running the best fluid you can and well matched track pads and still cooking them, then look at additional cooling.